Anything to keep in mind? Yep, if you have some sort of long term goal, like keep playing after 80 then you should level up with a premium account. While you can level without restrictions you miss out on some sweet bonuses like a free AA expertise point every level. It’s a huge difference starting level 80 with 79 expertise points, it allows you to unlock the most vital perks necessary for endgame 6man content asap.
If you plan on doing 6man content at 80 or want your characters to be the best it can be - subscribe to get membership perks.
If you plan on casually playing the 2 of you ignoring group content, dont bother subscribing.